So the third big update will be the shulker update. It will include the new shulker mob! These are my ideas!
Note: this is the 1.9.1
Nuke (does 30x the amount of damage as normal TNT)
Volcano - a giant map filled with obsidian and bedrock. At the center is a 100 block tall volcano! Islands or mountains on this map can contain villagers.
BIOME SPECIFICS: water gaiser
Beach - a smaller area of the beach with no sandstone or villages.
BIOME SPECIFICS: sand castle, lifeguard stand
Tornado - a whirling wind that destroys everything. Mobs will run from these. If anything gets within 15 blocks they will be hurled into the air from either 60-300 blocks in the air. These are either 9-50 blocks In height. Their width varies from 30-150 blocks wide. The only thing that won't get sucked in is obsidian, bedrock, endstone and cement or digging down 7 blocks.
Fire devil - similar to the tornado but its bottom half is burning and burns anything within 9 blocks will catch fire. These can only spawn in the nether. Their width varies from either 5-25 blocks. If one is spawning while you're in the nether, either dig 7 down or surround yourself with bedrock or obsidian.
Supercell - Also similar to the first 2, this one mainly spawns in the end (though there is a 2 percent chance of it spawning in the normal world). The bottom half is invisible except for the eye. Unlike the first 2, this one does neither fall nor fire dimage. This spawns in a severe thunder storm the same width is as it. There width verbs from 100-500 blocks.
Red lightning - this Is a variant of lightning that occurs when it hits redstone and also explodes the surface it touches.
Severe thunderstorm - a stronger variant of the storm that has a chance of spawning red lightning and hurricanes.
Hurricanes - strong gusts of wind capable of knocking down blocks.
Dust devils - a weak version of the tornado only lifting weak blocks and small mobs. They are clear. Their width varies from 3-15 blocks.
Earthquake - creates a revine and call cause structures to collapse.
Squirrel 2 HP (tameable)
Giant stick insect 4 HP
Parrot 2 HP
Prehistoric dragonfly 4 HP
Emporer Penguin 6 HP
Deer 10 HP (tameable)
Leatherback turtle 16 HP
Camel 20 HP (tameable)
African elephant 32 HP (tameable)
Giraffe 38 HP
Megatherium 46 HP
Parecetherium 52 HP
Whale Shark 82 HP (boss)
Sauroposeiden 184 HP (boss)
Seismosaurus 198 HP (boss)
Bootlace worm 360 HP (boss)
Amphicoelias 394 HP (boss)